How to successfully replace some of the flour with other ingredients?
I'm diabetic, so I'm looking for ways to lower carb count in a slice of bread. I'm also fairly new to bread baking, so I'm trying to gather as much info as I can before I start. I've been thinking about replacing a portion of the flour with less aggressive things like flaxseed, wheat bran, or similar, basically to bulk it up to the same size it would have been with the full amount of flour.
I'm not looking for one of these 0 carb contraptions found on the internet - there really isn't anything that can replace real bread made with real flour.
So my question here: How much of the flour can I successfully cut without ruining the bread? And are there any extra ingredients/steps that I would need to consider?
I'm looking to make plain and simple sandwich and toast bread that slices well and doesn't crumble when I try to make a sandwich. If you have any recipes for that, it would be amazing. I have all-purpose, whole wheat and rye flour but can make a trip to buy any other kind if necessary, and I don't have access to any baking technology except for a bread pan and 2 ovens (1 electric, 1 propane).